一件出土饱水木漆器文物中可培养细菌的鉴定及对木材的腐蚀作用

Identification of cultured bacteria separated from an excavated waterlogged wood and lacquer

【背景】饱水木质文物易受到微生物侵害,目前国外围绕饱水木质文物微生物病害已开展多方面研究,并取得阶段性进展,而国内在饱水木质文物微生物学技术方面的报道比较少。【目的】研究保藏水环境中出土饱水木漆器F446及水中细菌的种类,以及对木材的腐蚀作用。【方法】采用16S rRNA基因序列分析方法及生理生化试验,对饱水木漆器F446及水环境中细菌进行鉴定,并选取典型菌按5×10~8个/瓶菌量接种马尾松心材(悬于无菌自来水中),37°C培养120 d,测试木材的损失率。【结果】从F446文物和水样中分离的53株细菌中,21株被鉴定为芽孢杆菌属(Bacillus),为优势菌属,其中蜡样芽孢杆菌(B.cereus)19株,病研所芽孢杆菌(B.idriensis)和苏云金芽孢杆菌(B.thuringiensis)各1株;11株菌被鉴定为短杆菌属(Brevibacterium),此外还有4株短波单孢菌属(Brevundimonas),5株粪产碱杆菌(Alcaligenes faecalis),5株Altererythrobacter,2株水氏黄杆菌(Flavobacterium mizutaii);另外,还有解糖假苍白杆菌(Pseudochrobactrum saccharolyticum)、梭型芽孢杆菌(Lysinibacillus fusiformis)、Leucobacter aridicollis、Ochrobactrum pseudogrignonense、类芽孢杆菌属(Paenibacillus)菌株各1株。菌株A5、A6分别为类芽孢杆菌(Paenibacillus)和Altererythrobacter属中的疑似新种。从典型菌中选取15株菌回接木材进行腐蚀试验,结果显示,9株细菌与对照组比较存在极显著差异,说明这些菌对马尾松木材有一定的腐蚀作用,但是腐蚀率非常低,最高仅1.38%,表明这些细菌对试验木材马尾松腐蚀并不严重。【结论】F446木漆器文物样品中优势菌属为芽孢杆菌属(Bacillus),水样中优势菌属依次为短杆菌属(Brevibacterium)、短波单孢菌属(Brevundimonas)和Altererythrobacter。从F446木漆器文物和水样中分离出的细菌对木材的降解非常缓慢,短期内腐蚀作用有限。

[Background] According to relevant researches, waterlogged archaeological wood is vulnerable to degradation by microorganisms. Concerning the microbial damage of waterlogged archaeological wood, many studies have been carried out overseas, but few reported in China.[Objective] This study is aimed at analyzing the bacteria population in waterlogged archaeological wood and their degradation on wood when preserved in water. [Methods] Bacteria were identified by physiological and biochemical test and 16S rRNA gene sequence analysis. Typical bacteria strains were inoculated into wood that were used to test the wood degradation. The number of bacteria used to inoculate was 5×10~8 and the inoculated wood was cultured at 37 °C for 120 d. [Results] In total 53 strains were separated from F446 and the water sample. The dominant genus of these strains with number of 21, was Bacillus. Eleven of them belong to the genus of Brevibacterium, four are Brevundimonas, five are Alcaligenes faecalis, five are Altererythrobacter, two are Flavobacterium mizutaii, one is Pseudochrobactrum saccharolyticum, Lysinibacillus fusiformis, one Leucobacter aridicollis, one Paenibacillus, and one Ochrobactrum pseudogrignonense. Furthermore, strains A5 and A6 are likely new species of Paenibacillus and Altererythrobacter. Fifteen typical strains were selected to test the corrosion. Nine strains have extremely significant difference compared to the control. Some bacteria corroded wood but the corrosion rate was lower. It indicated that these bacteria could not cause severe corrosion to the wood of Pinus massoniana. [Conclusion] During a short period, bacterial driven wood-corrosion was not obvious when the archaeological waterlogged wood was preserved in water after excavated.